Automatic machineries can replace manpower and increase production speed and reduce costs. Assembly of machinery elements usually requires screws to fasten a plurality of objects together. In order to improve production efficiency and reduce cost using automatic equipments to fasten screws is a speedy solution. For instance, U.S. publication No. 20120067176 entitled “AUTOMATIC SCREW TIGHTENING APPARATUS” discloses a method and apparatus to tighten screws automatically.
Constant advance of integrated circuit manufacturing process and design has greatly improved performances and functions of electronic elements of a given size. On the other hand, digital products such as computers, communication electronic products and consumer electronics have rapid progresses that make their assembly increasingly difficult. For instance, now screws are almost smaller than 2 mm that are hard to be picked up for arrangement through the technique disclosed in the aforesaid U.S. publication No. 20120067176, thus tightening the screws is almost impossible. With the size of the screws become smaller, fastening difficulty also increases. Moreover, accurate alignment of screw holes and screws prior to fastening also becomes more challenging. As electronic products nowadays demand high degrees of precision, incomplete fastening of the screws into screw holes make the screws jutting to a higher elevation that affects coupling precision and assembly accuracy in the downstream processes. There are still rooms for improvement.